Minute quantities of nuclear fuel such as deuterium, tritium, and mixtures thereof are used in various devices to produce a burst of high energy gamma radiation, X-rays, fast neutrons, other forms of radiation, and fusion reactions. Examples of such devices are neutron generators, magnetic confinement devices, electrom beam fusion devices, and laser driven fusion devices. The fast neutrons and various forms of radiation produced from fusion fuel by such devices are useful in producing tritium, simulation studies of nuclear weapons, the testing and radiation hardening of materials, the testing of electronic systems such as those used in antiballistic missiles to determine their susceptibility to malfunctioning by being subjected to such radiation, sterlization of insects such as fruit flies, and medical research and treatment of tumors and various cancers.
The minute quantities of fusion fuel used in neutron generators and various fusion reactor devices are usually hydrogen isotopes in the form of solid slabs, cubes, or droplets. While these simple geometries have been adequate for some experimental tests, it is desirable to provide other fuel configurations in large quantities for use in such devices and when available, commercial fusion reactor operations.
To increase the yield of fast neutrons, high energy radiation, X-rays, and energy from fusion fuel when irradiated with laser energy, it is believed to be desirable to have the minute quantity of fusion fuel in the form of a small sphere of gas and preferably in the form of a solid hollow sphere. Such spherical configurations of fusion fuel, which can be referred to as a pellet, may have a diameter which varies all the way from 1/16 of a millimeter (mm) to approximately 2 mm or larger, but is preferably in the range of 1/8 to 1 mm. Such configurations of fusion fuel and methods and apparatus for utilizing laser energy to irradiate fusion fuel in such configurations to obtain a burst of high energy gamma radiation, X-rays, fast neutrons and a fusion reaction are disclosed in the copending U.S. application of Keith A. Brueckner, Ser. No. 337,094, filed Mar. 2, 1973 as a continuation-in-part of application, Ser. No. 12,624, filed Feb. 20, 1970, and copending U.S. application of Keith A. Brueckner, Ser. No. 377,508, filed July 10, 1973 as a continuation-in-part of application, Ser. No. 116,707, filed Jan. 29, 1971, which are incorporated herein by reference. All of these Brueckner patent applications are assigned to the assignee hereof.
Thus, the problems before the art are to provide spherical fuel pellets which can be accurately regulated in dimension and thus are more efficient in producing fast neutrons, high energy gamma radiation, X-rays, and other forms of radiation and more efficient in the ultimate fusion process, and also to provide fuel pellets with a spherical configuration which lends itself to an efficient fusion implosion by the input of laser energy and thus a higher yield of fast neutrons, high energy gamma radiation, X-rays, other forms of radiation, and energy.